Certain aminimides used to control bacteria and fungi

ABSTRACT

A class of aminimides structurally characterizable as dipolar ions wherein a quaternary nitrogen atom is directly bonded to the nitrogen anion of a long chain fatty amide exhibit broad spectrum inhibitory activity against gram positive bacteria and fungi.

BACKGROUND OF THE INVENTION

1. Field of the Invention

This invention relates to a class of nitrogenous compounds asantimicrobial agents for the control of bacterial and fungal growth.

2. Description of the Prior Art

Considerable effort has been directed during the past several decadestowards developing antimicrobial agents having a high activity against abroad spectrum of microorganisms including bacteria and fungi, but whichat the same time exhibit acceptably tolerable physiological properties.It is generally accepted that hexachlorophene of all of suchantimicrobials proposed to date comes about the closest to meeting thesedesiderata. Unfortunately the use of halogenated compounds of this typehas been severely restricted because of the recent unfortunate eventsstemming from what many feel amounted to a conspicuous misuse ofhexachlorophene. Accordingly a present need exists for an effectiveantimicrobial of this type devoid of the chemical characteristicsassociated with the indicated halogenated compounds.

It has recently been reported that certain fatty amines and fatty amidesevidence antimicrobial activity. Although the activity of thesecompounds fails to measure up to that demanded for a practicalantimicrobial agent, the low order of toxicity attributed to compoundsof this type renders these findings highly significant.

SUMMARY OF THE INVENTION

In accordance with the present invention a method is provided forinhibiting the growth of bacteria and fungi which comprises applying tosaid organisms or their loci an antimicrobially effective amount of acompound of the formula ##EQU1## wherein R represents a C₁₁ - C₁₇straight chain aliphatic hydrocarbon group and R' represents methyl,2-hydroxyethyl or 2-hydroxypropyl.

The antimicrobial agents of this invention in essentially microconcentrations exhibit surprisingly effective broad spectrum inhibitoryactivity against gram positive and fungal organisms. Moreover, thedipolar ion characteristics of these compounds contribute towards theirmarked hydrophilic nature and neutrality, which properties are importantin numerous use appliations especially where detergency constitutes anadjunct function.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

As indicated previously the practice of this invention resides in theuse of the antimicrobial agents described above as the active ingredientin a variety of conventional compositions for medicinal, cosmetic, ordisinfectant purposes. These compositions can be in the form ofsolutions, as well as solid, liquid or pasty suspensions and emulsionswherein the carrier or vehicle portion is water, oil, or an organicsolvent, such as, for example, ethanol. Likewise these compositions canbe solid admixtures including the pulverulent form thereof.

Representative of the foregoing compositions include cosmetic oils,salves, creams, pencils and powders; personal care items such as thespray, stick or powder deodorants, mouthwashes, hair rinses, skinlotions, foot powders and the like; and cleaning compositions such asdetergent bars, shampoos and toothpastes. Further, the antimicrobialagents of this invention can be advantageously employed in washing,rinsing, cleaning, disinfecting and preserving compositions fortextiles, leather, etc. Still a further important use of these agentscan be found in the cleaning and disinfecting compositions designed foruse in hospitals and such cleanliness sensitive industrialestablishments as dairies, breweries and laundries. The amount of theantimicrobial agent present in the contemplated compositions obviouslydepends on the particular use for which the overall composition isdesigned. Generally, in toothpaste, deodorants, cosmetics and footpowders and the like the amount of the antimicrobial agent ranges fromabout 0.1 to 3.0% based on the total weight of the composition. Inapplications of a cleansing or disinfecting nature as noted above, theconcentration of the agent in these instances can range up to about 10%.

The contemplated antimicrobial compounds of this invention wherein theindicated R' substituent is a hydroxy alkyl group can readily beprepared by reacting approximately stoichiometrical proportions of anapplicable fatty acid ester, preferably a lower alkyl ester thereof,1,1-dimethyl hydrazine and either ethylene or 1,2-propylene oxide.Examples of the applicable fatty acids for deriving a suitable esterthereof include lauric, myristic, palmitic, margaric, stearic and oleic.These acids are preferred since they are present in naturally occurringtriglyceride oils and thus are readily and economically obtained fromsuch sources.

The reaction can be effected simply by heating the indicated reactantsat a temperature preferably between 20° and 80° C. and recovering theproduct by the usual crystallization procedures. Complete detailsrelative to the above-described method for deriving the contemplatedaminimides can be found in U.S. Pat. No. 3,485,806.

Those aminimides useful in the practice of the present invention whereinthe indicated R' substituent is a methyl group can be prepared byseveral methods. The classical method is applicable for this purpose,which procedure consists of reacting a fatty acid chloride with1,1-dimethyl hydrazine followed by quaternizing the resultant acidhydrazide with a methyl halide and thereupon treating with a strong baseto effect dehydrohalogenation with the resultant production of thedesired aminimide. An alternate and more efficient manner of preparingthe instantly considered aminimides consists of reacting an ester of anapplicable fatty acid, preferably the lower alkyl esters, withapproximately an equivalent proportion of a trimethyl hydrazinium halidein the presence of an equivalent proportion of a strong base. Completedetails regarding this improved process can be found in U.S. Pat. No.3,706,800.

EXAMPLE

For the purpose of illustrating the antimicrobic activity of theaminimides of the present invention, five gram positive bacteria and tworepesentative fungi were used in a conventional test procedure fordetermining inhibitory effect. The identification of these testorganisms and their source follows:

      Organism         Source                                                     ______________________________________                                        Streptococcus faecalis (grp. D)                                                                Clinical Isolate                                             Streptococcus pyogenes                                                                         Clinical Isolate                                             Staphylococcus aureua                                                                          Hospital Infection                                           Corynebacterium  ATCC No. 10700                                               Nocardia asteroides                                                                            ATCC No. 3308                                                Saccaharomyces cerevisiae                                                                      Fleishman                                                    Candida albicans Michigan State University Plant                                               Pathology Fungi Collection                                   ______________________________________                                    

In the test procedure observed, representative aminimides were dissolvedin water or 95% ethanol to provide standard solutions having aconcentration of 1.0 mg of the test compound per ml of the solvent. Afurther test series was prepared by diluting with sterile Trypticase SoyBroth to concentrations of 100 ug/ml. Compounds more active than at 100ug/ml were further diluted in a subsequent test or tests.

Following the preparation of the test solutions as noted above, one drop(0.04 ± 0.01 ml.) of an 18-hour broth culture containing 10⁹ to 10¹²organisms per ml. was added to about 10 cc of each starting dilution ofthe indicated test compounds as well as to a like sample of plain brothserving as a positive control. After innoculation, the test samples arethoroughly mixed and then incubated at 35° C. in a 5% carbon dioxideatmosphere.

After an 18 hour period of incubation, the minimal inhibitoryconcentration (MIC) of each compound was determined for each testmicroorganism. The MIC value is defined as the lowest concentration(ug/ml) of the test compound at which no microscopic evidence of growthis observed. In the instances where the MIC exceeded 1000 ug/ml thecompound was rated non-inhibitory (NI). Under those circumstances wherethe test compound itself causes turbidity so that the MIC proveddifficult to determine in accordance with the above procedure, a sample(0.015 ml.) of the well-agitated broth or broths in question wereinnoculated into a Trypticase Soy agar plate containing 5% defibrinatedsheep blood. The test plate would then be incubated at 35° C. for 18hours and thereupon examined for growth.

The identification of representative compounds tested in accordance withthe following procedure together with the results obtained are outlinedin the following Tables.

                  TABLE I                                                         ______________________________________                                               OCH.sub.3 OH                                                                  ∥.sup.-.sup.+||                                    CH.sub.3 (CH.sub.2).sub.n --C--N--N----CH.sub.2 --CH.sub.2                    |                                                                    CH.sub.3                                                               COMPOUND - n =    10       12       14                                        ______________________________________                                        Streptococcus faecalis (grp. D)                                                                 100      10       100                                       Streptococcus pyogenes                                                                          100      10       10                                        Staphylococcus aureus                                                                           100      10       10                                        Corynebacterium sp.                                                                             100      10       10                                        Nocardia asteroides                                                                             100      10       10                                        Candida albicans  100      10       10                                        Saccharomyces cerevisiae                                                                        100      10       10                                        ______________________________________                                    

                  TABLE II                                                        ______________________________________                                               OCH.sub.3 OH                                                                  ∥.sup.-.sup.+||                                    CH.sub.3 (CH.sub.2).sub.n --C--N--N----CH.sub.2 CH--CH.sub.3                  |                                                                    CH.sub.3                                                               COMPOUND - n -  10     12     14   16    16*                                  ______________________________________                                        Streptococcus faecalis                                                                        100    100    100  100    1000                                (grp. D)                                                                      Streptococcus pyogenes                                                                        10     10     10   10     1                                   Staphylococcus aureus                                                                         100    10     10   100    10                                  Corynebacterium sp.                                                                           10     10     10   10     10                                  Nocardia asteroides                                                                           100    10     10   100    100                                 Candida albicans                                                                              100    10     10   1000   1000                                Saccharomyces cerevisiae                                                                      100    10     10   100    10                                  ______________________________________                                         *From oleyl                                                              

                  TABLE III                                                       ______________________________________                                                 O                                                                             ∥.sup.-.sup.+                                                        CH.sub.3 (CH.sub.2).sub.n --C--N--N(CH.sub. 3).sub.3                 COMPOUND - n =    10       12       14                                        ______________________________________                                        Streptoccus faecalis (grp. D)                                                                   1000     100      10                                        Streptococcus pyogenes                                                                          1000     10       10                                        Staphylococcus aureus                                                                           1000     10       10                                        Corynebacterium sp.                                                                             1000     10       10                                        Nocardia asteroides                                                                             1000     10       10                                        Candida albicans  1000     100      10                                        Saccharomyces cerevisiae                                                                        1000     10       10                                        ______________________________________                                    

What is claimed is:
 1. A method of inhibiting the growth of bacteria andfungi which comprises applying to said organisms or their loci anantimicrobially effective amount of a compound of the formula ##EQU2##wherein R is a C₁₁ - C₁₇ straight chain aliphatic hydrocarbon group andR' is methyl, 2-hydroxyethyl or 2-hydroxypropyl.
 2. The method of claim1 wherein said R' is methyl.
 3. The method of claim 2 wherein said R istridecyl or pentadecyl.
 4. The method of claim 1 wherein said R' is2-hydroxyethyl.
 5. The method of claim 4 wherein said R is tridecyl orpentadecyl.
 6. The method of claim 1 wherein said R' is 2-hydroxypropyl.7. The method of claim 6 wherein said R is tridecyl or pentadecyl.